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From: Murali Reddy <Murali.Reddy@citrix.com>
To: "cloudstack-dev@incubator.apache.org"
	<cloudstack-dev@incubator.apache.org>
Date: Wed, 30 Jan 2013 13:51:23 +0530
Subject: Re: [MERGE] merge 'events-framework' branch to master
Thread-Topic: [MERGE] merge 'events-framework' branch to master
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>
>Ok. this makes more sense as I think there would not be too many
>subscribers.
>So you would notify publisher that a new queue has been created? Otherwise
>how does publisher push the events out?

Generally idea of pub-sub model is that publisher/subscriber need not be
aware the existence of others. In the AMQP case, publisher just publishes
events to exchanges and not bother about the consumers. A subscriber
interested in a particular set of messages, will create a queue bound to
exchange with a binding key with pattern that describes interested
messages. It is message broker responsibility to match the message in
exchange with all binding key of the queue and deliver the message into
queue if message's routing key matches with binding key. So CloudStack
just publishes messages to an exchange, and creates a queue for each
subscriber and sets up call back to get notified If message gets into a
queue.